That the former has failed to prove his case, and that the latter has to some extent succeeded in doing so, may, or may not, be the fact; but it must be admitted that, if O’Brien was the more successful, he was not the more dexterous combatant. It has been frequently, and perhaps not without justice, remarked that “Irishmen have a way of _blundering_ upon the truth”; and from the eccentric fashion in which he sets about proving his contention, some may argue that O’Brien’s success merely affords an instance of this national peculiarity. But it would be hardly fair to do so in the case of an author who is acknowledged to have prepared himself for his task by careful study of the authorities bearing upon its subject, and whose “discovery,” as he calls it, is expressly founded on the results of that preparation. In this latter respect he presents a marked contrast to his somewhat dictatorial rival, who is wont to treat the exercise of private judgment by those who happen to differ from himself as a species of _lèse-majesté_.[18] On the other hand, O’Brien is always imploring the reader to follow his argument step by step. “Here,” he ever seems to be urging, “are the plain, unvarnished facts; here, the incontestable authorities; with these staring you in the face, surely you cannot think of denying that such and such an inference is unavoidable?” His reasons may not be always of the best; but, such as they are, he gives them freely. Of the two methods, the public, who are usually impressed by self-assertion, preferred the former; and “Dr. Petrie’s epoch-making book” was by general consent allowed to have “settled the question of the Round Towers for ever.” This comforting belief remained undisturbed for more than a quarter of a century, when, in the year 1867, a book appeared which challenged its infallibility. The author, a Mr. Marcus Keane, seems to have started upon an investigation of Irish ruins from sheer curiosity, and with a dispassionate intention to see and judge for himself. He was certainly not actuated by any wish to decry the merits of Petrie’s work, to which he confesses his great obligations, and which he appears to have taken at first as his guide. But, having carefully examined bit by bit the ancient architecture still remaining in most of the Irish counties, and having tested Petrie’s statements by personal investigation on the spot, he reluctantly confessed that he had lost faith in the latter. “After much consideration,” he declares,[19] “I have been forced to the conclusion ... that the generally received theory is not supported by sufficient evidence. My conviction of the heathen origin of these ruins has been strengthened in proportion to the increased knowledge which I have acquired by examination of the ruins themselves.... Not only the Round Towers, but also the crosses and stone-roofed churches are entirely of heathen origin.” Further, on all essential points he found himself in